Acyltransferase polynucleotides, polypeptides and methods of use

Abstract

The invention provides a novel DGAT1 protein with improved properties over known DGAT proteins, particularly known DGAT1 proteins from plants. The novel DGAT1 protein of the invention can be expressed in cells to increase cellular lipid accumulation. Expression of the DGAT1 protein of the invention in cells results in a higher level of lipid than any of several other plant DGAT1 proteins tested by the applicants. The invention provides polynucleotides encoding the novel DGAT1 protein of SEQ ID NO:39, constructs, cells, plant, plant parts and progeny comprising the polynucleotides, and methods of use of the polynucleotides and polypeptides of the invention.

The invention claimed is: 
     
       1. A cell transformed with a polynucleotide encoding a diacylglycerol acyltransferase 1 (DGAT1) polypeptide comprising at least one of:
 a) a sequence with at least 99% identity to the sequence of SEQ ID NO:39 
 b) the sequence of SEQ ID NO:39 
 c) a sequence comprising at least 450 contiguous amino acids of the sequence of a) or b), 
 
       wherein the polynucleotide is heterologous to the cell. 
     
     
       2. The cell of  claim 1  wherein the polypeptide has DGAT1 activity. 
     
     
       3. The cell of  claim 1 , wherein the DGAT1 polypeptide, when expressed in the cell has at least one of:
 a) higher DGAT1 activity than a DGAT1 protein having the amino acid sequence of SEQ ID NO: 44, and 
 b) altered substrate specificity relative to a DGAT1 protein having the amino acid sequence of SEQ ID NO: 44. 
 
     
     
       4. A genetic construct comprising a polynucleotide encoding a DGAT1 polypeptide comprising at least one of:
 a) a sequence with at least 99% identity to the sequence of SEQ ID NO:39 
 b) the sequence of SEQ ID NO:39 
 c) a sequence comprising at least 450 contiguous amino acids of the sequence of a) or b), 
 wherein the polynucleotide is operably linked to a promoter, and wherein the polynucleotide and the promoter are not found operably linked in nature. 
 
     
     
       5. A cell comprising a genetic construct of  claim 4 . 
     
     
       6. The cell of  claim 1  wherein the DGAT1 polypeptide has increased DGAT1 activity relative to a DGAT1 protein having the amino acid sequence of SEQ ID NO: 44. 
     
     
       7. The cell of  claim 1  wherein the DGAT1 polypeptide has altered substrate specificity relative to a DGAT1 protein having the amino acid sequence of SEQ ID NO: 44. 
     
     
       8. The cell of  claim 1  that produces more lipid than does a control cell that is not transformed with the polynucleotide. 
     
     
       9. The cell of  claim 1  that has an altered lipid profile relative to a control cell that is not transformed with the polynucleotide. 
     
     
       10. The cell of  claim 1  that is a plant cell. 
     
     
       11. The cell of  claim 1  that is also transformed to express at least one of: an oleosin, steroleosin, caloleosin, polyoleosin, and an oleosin including at least one artificially introduced cysteine. 
     
     
       12. A plant comprising the cell of  claim 1 . 
     
     
       13. A plant comprising a genetic construct of  claim 4 . 
     
     
       14. A plant comprising a plant cell of  claim 10 . 
     
     
       15. The plant of  claim 12  wherein the plant, or its predecessor, has been transformed or genetically modified to express the polynucleotide or encoded polypeptide. 
     
     
       16. The plant of  claim 12  wherein the polypeptide expressed by the polynucleotide has increased DGAT1 activity relative to a DGAT1 protein having the amino acid sequence of SEQ ID NO: 44. 
     
     
       17. The plant of  claim 12  wherein the plant produces more lipid, in at least one of its tissues or parts, or as a whole, than does a control plant that is not transformed with the polynucleotide. 
     
     
       18. The plant of  claim 12  wherein the plant has an altered lipid profile, in at least one of its tissues or parts, or as a whole, relative to a control plant that is not transformed with the polynucleotide. 
     
     
       19. The plant of  claim 12  wherein the plant is also transformed to express at least one of: an oleosin, a steroleosin, a caloleosin, a polyoleosin, and an oleosin including at least one artificially introduced cysteine. 
     
     
       20. A part, propagule or progeny of the plant of  claim 12 , wherein the part, propagule or progeny comprises the cell. 
     
     
       21. A part, propagule or progeny of the plant of  claim 13  wherein the part, propagule or progeny comprises the construct. 
     
     
       22. The part, propagule or progeny of  claim 20  wherein at least one of the following applies:
 the part, propagule or progeny produces more lipid than does a control part, propagule or progeny, or part, propagule or progeny of a control plant, and 
 the part, propagule or progeny has an altered lipid profile relative to a control part, propagule or progeny, or part, propagule or progeny of a control plant, 
 
       wherein the control part, propagule or progeny, or part propagule or progeny of the control plant is not transformed to comprise the polynucleotide. 
     
     
       23. The part, propagule or progeny of  claim 21 , wherein at least one of the following applies:
 the part, propagule or progeny produces more lipid than does a control part, propagule or progeny, or part, propagule or progeny of a control plant, and 
 wherein the part, propagule or progeny has an altered lipid profile relative to a control part, propagule or progeny, or part, propagule or progeny of a control plant,
 wherein the control part, propagule or progeny, or part propagule or progeny of the control plant does not comprise at least one of: 
 a) a sequence with at least 99% identity to the sequence of SEQ ID NO:39 
 b) the sequence of SEQ ID NO:39 
 c) a sequence comprising at least 450 contiguous amino acids of the sequence of a) or b). 
 
 
     
     
       24. An animal or biofuel feedstock comprising a cell transformed with a polynucleotide encoding a polypeptide comprising at least one of:
 a) a sequence with at least 99% identity to the sequence of SEQ ID NO:39 
 b) the sequence of SEQ ID NO:39 
 c) a sequence comprising at least 450 contiguous amino acids of the sequence of a) or b), 
 wherein the polynucleotide is heterologous to the cell. 
 
     
     
       25. An animal feedstock or biofuel feedstock comprising at least one plant part, propagule or progeny as defined in  claim 22 . 
     
     
       26. A method for producing a lipid, the method comprising growing a cell, plant cell or plant that is transformed, or genetically modified, with a polynucleotide encoding a diacylglycerol acyltransferase 1 (DGAT1) polypeptide comprising at least one of:
 a) a sequence with at least 99% identity to the sequence of SEQ ID NO:39 
 b) the sequence of SEQ ID NO:39 
 c) a sequence comprising at least 450 contiguous amino acids of the sequence of a) or b), 
 wherein the cell, plant cell, or plant produces oil through the activity of the expressed polypeptide, and 
 wherein the polynucleotide is heterologous to the cell. 
 
     
     
       27. The method of  claim 26  wherein the cell, plant cell or plant produces the lipid as a result of the DGAT1 activity of the polypeptide. 
     
     
       28. A method for producing lipid, the method comprising extracting lipid from at least one cell of  claim 14 . 
     
     
       29. The method of  claim 26  wherein the lipid is triacylglycerol (TAG). 
     
     
       30. The method of  claim 26  wherein the lipid is processed into at least one of:
 a) a fuel, 
 b) an oleochemical, 
 c) a nutritional oil, 
 d) a cosmetic oil, 
 e) a polyunsaturated fatty acid (PUFA), and 
 f) a combination of any of a) to e).